Just did a round trip for a cruise with Royal. We made our own reservations with Delta and chose their Comfort + seats, well worth the extra charge. There were two of us and since we made our reservations early we got the two seat configuration (2 - 5 - 2) which was easy to get in and out for restroom and walks.
We stayed at the Apolo Barcelona by Milea and toured the day we got in. We took the Hop-On Hop-Off bus which was within a short walking distance of the hotel. We ate dinner at the Listo Restaurant near the hotel which was delicious. The breakfast at the hotel was great. Las Ramblas is also within a short walking distance of the hotel. We only stayed one night but should have done two nights so we could have seen more of Barcelona.